I'm going to (actually already have) severely cut back on the amount of time I spend at HN, Reddit and other social sites. It's just not a productive use of my time, and life is too short to fritter away the hours doing nothing.
How? Just stop. You can't peek. You can't view it for "just a minute." You can't "just browse." The only solution is to not visit at all.
Give it a few days and it'll fall out of your daily routine altogether.
Also: edit your history to remove all reddit history so your browser navbar doesn't auto-complete when you reflexively open a new tab and start typing "re...".